Elastomeric polyurethanes derived from polyethers or polyesters, diisocyanates and diaminooxamides



United States Patent 3,249,577 ELASTOMERIC POLYURETHANES DERIVED FROMPOLYETHERS 0R POLYESTERS, DI- ISOCYANATES AND DIAMINOOXAMIDES Andre Rioand Jean Andre Robin, Lyon, Rhone, France, assignors to Rhone-PoulencS.A., Paris, France, a French body corporate No Drawing. Filed July 26,1963, Ser. No. 297,939 Claims priority, application France, Aug. 1,1962,

Claims. in. 26032.6)

This invention relates to elastomeric polymers derived from linearpolyesters of polyethers of low molecular weight.

The elastomeric polyurethanes of the invention consist substantiallycompletely of units of the formula:

where T is a divalent aliphatic, cycloaliphatic or aromatic radical, Ris a divalent aliphatic, cycloaliphatic or aromatic radical, and Z is apolyester or polyether residue such that the compound HOZOH is a linear,hydroxy-terminated polyester or polyether of molecular weight 500 to2500.

These new polyurethanes may be used in the preparation of fiexible andelastic filaments and films having good stability to light and heat.

They are prepared in accordance with the invention, by first reacting apolyester or polyether of formula HOZOH with at least two molecularproportions of a diisocyanate of formula: OCN-T-NCO, and then reactingthe isocyanate-terminated polymer thus obtained with one molecularproportion of a diaminooxamide of formula:

The isocyanate-terminated polymer obtained at the end of the firstreaction has the formula:

In the second reaction, this isocyanate-terminated polymer links withthe diaminooxamides with the formation of urea functions to give thepolyurethanes of the invention.

The polyesters employed in the preparation of the new polymers arelinear, hydroxy-terminated condensation products, having a molecularweight of 500 to 2500, especially 1200 to 2000, of aliphatic and/orcyclic diacids with aliphatic and/or cyclic diols. They have asubstantially zero acid number to avoid the formation of secondaryproducts which might result from the action of free acid groupings onthe diisocyanates and diamines with which they are reacted. Suchpolyesters are, for example, the products of condensation of aliphaticdicarboxylic acids of formula HOOC(CH COOH where n is 2 to 8, e.g.,:adipic acid, or of terephthalic acids with an alkylene glycol of 2 to 4carbon atoms, e.g., ethylene or propylene glycol or both. Instead ofsuch polyesters, there may, for example, be used polyethers, consistingof units of formula C H O where m is 2 to 4 linked together into a chainterminated by hydroxyl groups, especially polytetramethylene glycol,resulting from the polymerization or ec-polymerization of olefineoxides, such as ethylene or propylene oxides, or of tetrahydrofuran.These polyethers also have a molecular weight of 500 to 2500, preferably500 to 1000.

The diisocyanates OCNTNCO which are reacted with the polyesters ofpolyethers are aliphatic, cycloaliphatic or aromatic diisocyanates andinclude especially ene of 2 to 10 carbon atoms or a group of formua:

such as, for example, 1,6-diisocyanatohexane, the isomericdiisocyanatotoluenes, and p,p'-diisocyanatodiphenylmethane. They maycomprise non-reactive functional groupings other than their isocyanatefunctions, such as in p,p-diisocyanatotolyl urea.

The diaminooxamides used in making the polyurethanes of the inventionare obtained by reacting an excess of primary aliphatic, cycloaliphaticor aromatic diamine with an aliphatic or aromatic diester of oxalicacid. These oxamides are crystallisable solids which are soluble inwater and certain organic solvents such as dimethylformamide anddimethylsulphoxide. They are preferably obtained from alkylene diaminescontaining 2 to 6 carbon atoms, or from phenylene diamines. For example,there may be employed N,N'-bis(2-aminoethyl)oxarnide, N,N bis(2amin-opropyl)oxamide or N,N-bis (p-aminophenyDoxamide, which are readilyprepared by reacting ethylenediamine, 1,2-diaminopropane orp-phenylenediamine respectively with ethyl or phenyl oxalate.

The reaction of the diisocyanates with the starting polyethers orpolyesters is readily effected by heating in an inert anhydrousnon-volatile solvent which preferably has a sufiiciently low boilingpoint to enable it to be eliminated at the end of the reaction by simpleheating; chlorinated aliphatic hydrocarbons such as chloroform ordichloromethane are especially suitable. This elimination of thesolvent, however, is not essential and the diaminooxamide in solutionmay be directly added to the reaction mass. Since the reaction of theisocyanate-terminated polymer with the diaminooxamide is rapid andgenerally exothermic, the reaction mass must be generally cooled toabout 0 C. The latter reaction may also be carried out in a solvent forboth the isocyanate-terminated polymer and the diaminooxamide, forexample dimethylformamide. Polymer solutions are thus obtained which canbe directly cast or spun by known methods, to give flexible, elasticfilaments and films which have a high melting point and do not yellowunder prolonged exposure to light.

The following examples describe the preparation of certain preferredpolyurethanes of the invention.

Example 1 Into a 250-cc. spherical flask are introduced 29.4 g. of anethyleneglycol/propyleneglycol adipate polyester (obtained using equalweights of the two glycols) having a molecular weight of about 1500 anda hydroxyl number of 77. There are then added 10 g. ofp,p'-diisocyanatodiphenylmethane in solution in 70 ml. ofdichloromethane, and the reaction mass is gradually heated to theboiling temperature of the solvent, which is eliminated in the course ofthe reaction. Heating is continued at about C. for 1 hour after thecomplete disappearance of the solvent, and the product is then allowedto cool to ambient temperature and taken up with ml. ofdimethylformamide. Into the solution thus obtained, cooled to 0 C., isrun a solution of 3.48 g. of N,N'-bis (2-arninoethyl)oxamide in 100 ml.of dimethylformamide. There is thus obtained a polyurethane solutionwhich may be employed for the manufacture of elastic filaments andfilms. Films obtained, e.g. by casting, have a tensile strength of 273kg./cm. an elongation at break of 3 514%, and a modulus of elongation at300% of 200 kgn/cm. (tests according to standard NF T 46,002).

Example 2 By proceeding as in Example 1, but replacing thep,p-diisocyanatodiphenylmethane by 6.7 g. of 1,6-diisocyanatohexane,there is obtained a polymer which is soluble in dimethylformamide andfrom which there are obtained films having the followingcharacteristics: tensile strength=341 kg./cm. elongation at break=825%;and modulus at elongation at 300%:151 kg./cm. These films are verystable to light. When exposed for 70 hours to the ultra-violet rays froma mercury vapour lamp, they do not yellow.

If this test is repeated, replacing the N,N'-bis(2-aminoethyDoXamide by0.768 g. of hydrazine, when the running-in of the hydrazine solution iscomplete, the reaction mass sets to a thick gel, from which no polymercan be separated and which cannot be directly used in the preparation offilms.

Example 3 By proceeding as in Example 1, but replacing N,N'- bis(2aminoethyDoxamide by 4.04 g. of N,N bis(2- aminopropyl)-oxamide, thereis obtained a clear, spinnable polyurethane solution in di-methylformam-ide from which films are produced, which have a tensile strength of380 kg./cm. and an elongation at break of 670%.

Example 4 Proceeding as in Example 1, there are reacted with the samequantity of the same polyester, first 6.7 g. of 1,6-diisocyanatohexaneand then 4.04 g. of N,N-h=is(2- aminopropyDoxamide in solution indimethylformatmide. A polyurethane solution is obtained, from which canthe obtained films which do not yellow after exposure -to ultravioletrays tfor 70 hours. These films have a tensile strength of 240 leg/cm.and an elongation at break of 860%.

It the same test is repeated, replacing the N,N'-bis(2-aminopropyDoxamide by an equivalent quantity of ethylenediamine, thereis obtained at the end of the reaction of a gel which cannot be cast.

Example 5 By reacting 30 g. of the ethyleneglycol/propyleneglycolpolyadipate of Example 1, first with g. ofp,pdiisocyanatodiphenylmethane and then with 5.72 g. ofN,N'-bis(6-aminohexyl)oxamide, under the conditions of Example 1, apolyurethane which can the cast into elastic films is obtained.

Example 6 With 20 g. of polytetramethyleneglycol, having a molecularweight of about 700, there are successively reacted, by the procedure ofExample 1, 10 g. of p,p'-diisocyanatodiphenylmethane and 3.48 g. ofN,Nbis(2- aminoethyDoXamide in solution in dimethylformamide. A clear,homogeneous polyurethane solution is thus obtained which can be directlyemployed for the production of flexible and elastic films and filaments.

We claim:

1. Elastomeric polyurethanes consisting substantially completely ofunits of the formula:

T is a divalent radical selected from the group consistof d illfillsaturated unsubstituted aliphatic chains containing 2 to 10 carbonatoms, phenylene, tolylene',

and groups of formula:

R is a divalent radical selected from the group consisting of saturatedunsubstituted aliphatic chains containing 2 to 6 carbon atoms andphenylene, and Z is such that the compound HO-ZOH has a molecular Weightof 500 to 2500 and is either (i) a linear, hydroxy-terminated polyesterderived from an aliphatic dicarboxylic acid of formula HOOC(CH ),,COO-Hwhere n is 2 to 8 or terephthalic acid and an alkylene glycol of 2 to 4carbon atoms or (ii) a polyether consisting of units of formula C H Owhere m is 2 to 4 linked into a chain terminated by hydroxyl groups.

2. Elastomeric polyurethanes as claimed in claim 1, in in which T ishexamethylene.

3. Elastomeric polyurethanes as claimedin claim 1 in which Z is suchthat the compound HOZ-OH is a linear, hyd-roxy-terminated polyester ofmolecular weight of 500 to 2500 formed by condensing an alkylene glycolof 2 to 4 canbon atoms with terephthalic acid.

4. Elastomeric polyurethanes as claimed in claim 1 in which T is 5.Elastomeric polyurethanes consisting substantially completely of unitsof the formula:

linked together by bonds from terminal C to terminal NH and havingendradicals of formula attached to CO- and H attached to NH- where T isselected from the class consisting of hexa methylene and CONHTNH-COOZ-OCONHT-NHCO-NH -R-NH--COCO-NlIR-NH- linked together by bonds fromterminal -C0 to terminal --NH- and having end radicals of formulaattached to -CO and -H attached to NH- where T is selected fromthe'class consisting of hexamethylene and R is alkylene of 2 to 6caribon atoms, and Z is such that the compound HO-ZOH is a linear,hydroxy-tenminated polytetramethylene glycol of molecular weight 500 to2500.

7. Elastomeric polyurethanes consisting substantially completely ofunits of the formula:

linked together by bonds from terminal CO to terminal -'NH and havingend radicals of formula attached to CO- and H attached to NH- where T isselected from the class consisting of hexamethylene and substantially.linked together by bonds from terminal CO to terminal NH- and havingend radicals of formula H N -RHNCO-CO-NHRNH attached to CO and Hattached to NH- where T is selected from the class consisting ofhexamethylene and R is alkylene of 2 to 6 carbon atoms, and Z is suchthat the compound HO-ZOH is a linear, hydroXy-terminatedpolytetramethylene glycol of molecular Weight 500 to 1000.

9. Solutions of elastomeric polyurethanes consisting substantiallycompletely of units of the formula:

linked together by bonds from terminal CO- to terminal NH- and havingend radicals of formula attached to CO and H attached to NH- where T isa divalent radical selected from the group consisting of divalentsaturated unsubstituted aliphatic chains containing 2 to 10 carbonatoms, phenylene, tolylene, and groups of formula:

R is a divalent radical selected from the group consisting or"saturate-d unsubstituted aliphatic chains containing 2 to 6 carbon atomsand phenylene, and Z is such that the compound HOZ-OH has a molecularweight of 500 to 2500 and is either (i) a linear, hydroxy-terminatedpolyester derived from an aliphatic dicarboxylic acid of formula HOOC(CH),,COOH where n is 2 to 8 or terephthalic acid and an alkyl'ene glycolof 2 to 4 carbon atoms or (ii) a polyether consisting of units offormula C H O where m is 2 to 4 linked into a chain terminated byhydroxyl groups.

10. Solutions in di methylformamide of elastomeric polyurethanesconsisting substantially completely of units of the formula:

linked together by bonds from terminal CO to terminal NH and having endradicals of formula attached to CO- and H attached to NH where T is adivalent radical selected from the group cons-isting of divalentsaturated unsubstituted aliphatic chains containing 2 to 10 carbonatoms, phenylene, tolylene, and groups of formula:

R is a divalent radical selected from the group consisting of saturatedunsubstituted aliphatic chains containing 2 to 6 carbon atoms andphenylene, and Z is such that the compound HOZOH has a molecular weightof 500 to 2500 and is either (i) a linear, hydroxy-tterrninatedpolyester derived from an aliphatic dicarboxylic acid of formula HOOC(CHCOOH where n is 2 to 8 or terephthalic acid and an alkylene glycol of 2to 4 carbon atoms or (ii) a polyether consisting of units of formula C HO where m is 2 to 4 linked into a chain terminated by hydroxyl groups.

References Cited by the Examiner UNITED STATES PATENTS 2,983,702 5/196-1 Little et al. 260-77.5 3,012,992 12/ 196 1 Pigott et al. 260'753,043,807 7/1962 Snyder et al. 260- 3,087,912 4/1963 Wagner et al26077.5 3,105,062 9/ 1963 Graham et al 260-75 3,114,734 12/ 1963Gorb-ran et a'l 260-75 MORRIS LIEBMAN, Primary Examiner.

10. SOLUTIONS IN DIMETHYLFORMAMIDE OF ELASTOMERIC POLYURETHANESCONSISTING SUBSTANTIALLY COMPLETELY OF UNITS OF THE FORMLA: